1Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo 105-8461, Japan2Institute of Clinical Medicine and Research, The Jikei University School of Medicine, Tokyo 105-8461, Japan3Department of Oncology, Institute of DNA Medicine, The Jikei University School of Medicine, Tokyo 105-8461, Japan4Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA